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The impact of substituting K2O for Na2O (0–100%) on the physico-chemical and bioactive properties of bioactive glass S53P4 was studied. The thermal properties were evaluated using differential thermal analysis and high-temperature microscopy. Ion release kinetics was measured in static and dynamic TRIS-buffer and SBF using inductively coupled plasma optical emission spectroscopy. Substituting K2O for Na2O showed a mixed-alkali effect (MAE) for the thermal properties with a minimum value for the glass containing around 20% K2O. The hot-working range increased with the potassium content. The glass with 66% of Na2O replaced with K2O exhibited MAE in static TRIS by giving the biggest pH change and ion release at 24 h. The same glass showed the lowest pH and Si species release in dynamic SBF at the longest dissolution time, 72 h. Both single-alkali glasses showed higher in vitro bioactivity in dynamic SBF. The results provide tools for tailoring new bioactive glass compositions with desired properties.

Isothermal compression behaviors of as-extruded AA 2055 alloy (T6 state) were studied at temperature of 320, 380, 440 and 500 °C with strain rate of 0.001, 0.01, 0.1 and 1 s−1 by a Gleeble-3800 testing machine. A modified Johnson–Cook model fitted by polynomial and power-exponential functions were established to describe the flow stress of the alloy. The constitutive models fitted by higher-order polynomials were more accurate than the ones fitted by second-order polynomial and power-exponential functions. The constitutive model fitted by a fourth-order polynomial was chosen for the optimal constitutive model in order to balance the prediction accuracy and model complexity. The modified Johnson–Cook constitutive model could predict the flow stress well, especially in high-temperature zone (around 500 °C) and low-temperature zone (around 320 °C). The dynamic precipitation and dissolution of the T1 phase during hot compression were discussed. The unusual dynamic precipitation of the T2 phase was investigated during hot compression by XRD and TEM. The massive dense fine precipitates effectively pinned dislocations or subgrain boundaries to accelerate DRV but suppressed DRX, leading to a low frequency of HAGBs in compressed samples. [ABSTRACT FROM AUTHOR]

In vitro reactions of granules and microspheres (45–90 µm) of the bioactive glass S53P4 and an experimental composition with 5 mol.% K 2 O substituted for Na 2 O in S53P4 were studied in continuous fluid flow conditions. The dissolution experiments were performed with a 0.2 mL/min flow rate in TRIS buffer up to 24 h. Granules provided higher initial release and pH changes, while at the longest time point, 24 h, the release of Na+K, Ca, and Si was similar for granules and microspheres. The reaction layers (Si-rich and CaP) were evaluated via SEM-EDX analysis. Granules exhibited a thicker Si-rich layer than the microspheres of both glasses. At the same time, a more developed CaP surface layer was detected for S53P4 microspheres than granules. Microspheres, with their uniform shape and size distribution, provided a controlled porosity in the reactor, allowing a more uniform solution flow through the particle bed. A shrinking core model based on the external mass transport coefficient, diffusion through the Si-rich layer, and dissolution rate coefficient was used to predict the initial dissolution kinetics of the glass microspheres in the TRIS buffer. The calculated model parameters provided an appropriate fit with the experimental data for the calcium and alkalis release from the microspheres. The results imply that microspheres offer a good platform for calculating the model parameters for predicting the dissolution mechanism of silicate-based bioactive glasses. [ABSTRACT FROM AUTHOR]

Developing energy- and time-efficient strategies to derive high-performance non-precious electrocatalysts for anodic oxygen evolution reaction (OER), especially stably working at industrial-demanding current density, is still a big challenge. In this work, a concise molten salt erosion scenario was devised to rapidly modulate the smooth surface of the commercial NiMo foam substrate into the rough, electronically coupled, and hierarchically porous Ni/Fe/Mo(oxy)hydroxide catalyst layer assembled by the nanosphere array. This self-supported catalyst is super-hydrophilic for the alkaline electrolyte and distinguished by a balanced Mo leaching/surface-readsorption process to tune the metal d band center and electronic perturbation. The altered electronic environment with the favored OER intermediate adsorption behavior attains the outstanding OER activity in terms of a very small overpotential of 230.21 mV at 10 mA cm -2 and an ultra-long stability for 1179.45 h to sustain the initial commercial-level current density of ca. 1000 mA cm -2 . This superb performance transcends most of the edge-cutting transition metal peers reported recently and can satisfy the standards of industrial applications. This industrial-compatible synthesis technology holds profound implications for hydrogen production via water splitting and other electrochemical applications., (© 2024 Wiley-VCH GmbH.)

The aim of this work was to investigate the use of carbon dioxide (CO2) laser irradiation to modify three types of pH-dependent Eudragit® (L100-55, L100, and S100) enteric coats with the aim of modulating drug release kinetics from the tablet cores. CO2 laser irradiation causes rapid melting and resolidification/vaporization of materials locally and precisely through the absorption of infrared energy and so can potentially disrupt the barrier integrity and function of enteric coats. It was successfully utilized to shorten the lag time of drug release (T50% and T80%) during dissolution testing. These changes were mainly caused either by pore formation on the surface of the coating and/or loosening of the film coat. In addition, changes in mechanical properties (Young's modulus and tensile strengths) and shifted IR peaks of the irradiated coatings were found, which correlated with drug release rates. This work is a proof-of-concept of tailoring drug release profiles by adjusting the power of the laser energy which could be useful for the modification of drug release for personalized medicines. [ABSTRACT FROM AUTHOR]

Isothermal compression behaviors of as-extruded AA 2055 alloy (T6 state) were studied at temperature of 320, 380, 440 and 500 °C with strain rate of 0.001, 0.01, 0.1 and 1 s−1 by a Gleeble-3800 testing machine. A modified Johnson–Cook model fitted by polynomial and power-exponential functions were established to describe the flow stress of the alloy. The constitutive models fitted by higher-order polynomials were more accurate than the ones fitted by second-order polynomial and power-exponential functions. The constitutive model fitted by a fourth-order polynomial was chosen for the optimal constitutive model in order to balance the prediction accuracy and model complexity. The modified Johnson–Cook constitutive model could predict the flow stress well, especially in high-temperature zone (around 500 °C) and low-temperature zone (around 320 °C). The dynamic precipitation and dissolution of the T1 phase during hot compression were discussed. The unusual dynamic precipitation of the T2 phase was investigated during hot compression by XRD and TEM. The massive dense fine precipitates effectively pinned dislocations or subgrain boundaries to accelerate DRV but suppressed DRX, leading to a low frequency of HAGBs in compressed samples.

[Display omitted] Food and formulation characteristics are crucial factors affecting the gastrointestinal release and absorption kinetics of oral solid preparations. In the present study, the dynamic continuous release and bioaccessibility of metformin hydrochloride immediate-release (IR) and sustained-release (SR) tablets were investigated in the dynamic human stomach-intestine (DHSI-IV) system simulating fasted and fed states in healthy adults. Both tablet formulations (particularly IR tablet) exhibited a postponed release in the fed state compared to the fasted state. Correspondingly, the bioaccessible fraction of metformin from IR tablets in the presence of high-fat meal was significantly reduced to 76.2 % of the fasted state. However, the in vitro bioaccessibility was less impaired by food for SR tablets with a fed/fasted ratio of 95.5 %. A convolution-based approach was used to convert in vitro bioaccessibility results to plasma concentration data. The predicted plasma concentration curve showed good agreement with human data in terms of pharmacokinetic (PK) parameters. In the fasted state, the predicted C max , T max and AUC 0-24h of IR tablets were 943.9 ± 25.7 ng/mL, 2.0 ± 0.4 h and 7090.7 ± 112.0 ng.h/mL, respectively, mirroring values observed in healthy subjects. Overall, the DHSI-IV system has demonstrated potential to assess and predict the impact of meal intake on the in vivo release and absorption behaviors of oral solid preparations. [ABSTRACT FROM AUTHOR]

To understand the bioaccessibility of cadmium（Cd）in compound-contaminated soils containing cadmium and ciprofloxacin, uncontaminated soils were artificially polluted with cadmium and ciprofloxacin at 4 different treatment rates（CK:0mg·kg-1, CIP：I5mg·kg-1,II25mg kg-1, andIII50mg kg-1; Cd：80mg·kg-1）. A pot experiment was performed with three soil aging times to investigate the risk of Cd to human health using in vitrodigestion method and SHIME model. The results showed that there was no significant difference in the bioaccessibility of Cd among different soil aging times in compound-contaminated soils. Besides, the bioaccessibility of Cd decreased with soil aging time（D60

Composites have been manufactured based on a mixture of calcium phosphates and an alginate-chitosan polyelectrolyte complex (PEC). The properties of these composites can be tuned by varying the filler/matrix ratio and drying temperature, so these materials may be regarded as potentially usable in orthopedics and traumatology. The composition and morphology of the manufactured samples and their dynamic dissolution have been studied. The embedding of a powder material into the PEC matrix does not change the matrix composition, but increases the resorption rate of the sample. Optimal synthetic conditions have been chosen for the composites, namely, the filler/matrix ratio and the drying temperature and time. [ABSTRACT FROM AUTHOR]

We have prepared a composite material based on a mixture of calcium phosphates and sodium alginate and investigated their composition, morphology, and dynamic dissolution behavior. The addition of a powder material to the sodium alginate matrix causes no changes in its composition, but increases the specific surface area and resorption rate of the sample. We have optimized the synthesis conditions of the composite material: the filler/matrix ratio and the drying temperature and time. [ABSTRACT FROM AUTHOR]

Abstract The release of therapeutic ions during dissolution is necessary for the success of bioactive glasses in medical applications. Therefore, different borate and borosilicate glasses undoped and doped with copper or/and zinc based on the 13–93 composition were tested and compared to the well-known 13–93 bioactive glass in several dissolution media. Prior to dissolution studies, all glasses were characterized using SEM-EDX, FTIR, XRD, DTA and hot stage microscopy (HSM). Dissolution studies were carried out using tris(hydroxymethyl)aminomethane (TRIS) buffer and simulated body fluid (SBF) under static conditions. The dissolution rates varied following the trend of borate glasses > borosilicate glasses > silicate glasses. Further, the release of boron from both borate and borosilicate glasses was inhibited in SBF compared to TRIS. The dissolution of the glasses was additionally tested in SBF under dynamic conditions to better mimic the human body environment. Under these conditions, Cu-doped glass released up to 10 mg/L of Cu2+, which is the critical biological level of Cu2+ for the survival of fibroblasts. In order to mimic the conditions that may develop locally during the degradation of a poly(lactic acid) (PLA) composite or during a bacterial infection, dissolution studies were for the first time also carried out using a lactic acid solution at pH = 2. Zinc was only released from the Zn-doped glasses under acidic conditions. Owing to the antibacterial property of Zn2+, these results are especially interesting for the application of the ion-doped glasses in the treatment or prevention of infections. Highlights • Systematic characterization of dissolution behavior of several glass compositions. • Silicate, borate compositions dissolve differently depending on dissolution media. • During dynamic dissolution, Cu could be controlled released up 10 mg/l. • Zn could be released in acid conditions during dissolution, not in neutral conditions. [ABSTRACT FROM AUTHOR]

We have synthesized octacalcium phosphate (OCP) in the presence of inorganic additives (magnesium, strontium, and fluoride ions) and studied the composition, morphology, thermal stability, and dynamic dissolution of the samples thus obtained. It has been shown that, in addition to OCP, magnesium and strontium ions favor the formation of brushite and hydroxyapatite (HA), whereas fluoride ions favor the formation of HA and fluorohydroxyapatite (FHA). We have proposed a process for the preparation of powder materials whose resorption kinetics in corrosive liquid media are corrected by adding dopants capable of activating the dissolution process. [ABSTRACT FROM AUTHOR]

The microstructure of a rare earth containing magnesium alloy, Mg-4.35Y-3RE-0.36Zr wt%, was engineered through applying accumulative back extrusion (ABE) process. Toward this end, the predetermined ABE cycles were applied at 400 °C up to five passes under a punch speed of 5 mm/min to study the ultrafine grained microstructure formation and its corresponding texture modification in the experimental material. A variety of bimodal grain size distributions were developed at all deformation conditions. In addition, the dissolution of eutectic phase stimulated the probability of dynamic precipitation of β phase during deformation. The latter caused a pinning effect on the grain boundary and gave rise to an inhomogeneous grain growth thereby intensified a bimodal grain size distribution (bimodality). In addition, the capability of experimental material to shear band formation during straining, even after one ABE pass, induced the level of bimodality. A remarkable grain refinement was achieved inside the shear bands due to the higher magnitude of shearing strain. Furthermore, the shear bands intersections provided suitable conditions for well defined ultrafine grain formation in between primary bands. The formation of noticeable number of these ultrafine grains within the shear bands could decrease the basal intensity thereby inducing a significant texture weakening effect. The obtained results indicated a significant improvement in both the strength (yield and ultimate) and elongation to fracture of the processed material. This was justified considering the effects of grain size, the level of bimodality and the texture weakening. [ABSTRACT FROM AUTHOR]

• Tiny microspheres in sizes 45–90 and 90–125 µm were flame-sprayed from bioactive glass S53P4 without alkali volatilisation. • The microspheres gradually dissolved in simulated body fluid and TRIS-buffer solutions under a dynamic environment. • Thicker silica-rich and calcium phosphate layers formed in vitro on the spheres of the larger size range. • S53P4 and 13–93 microspheres had a similar ability to form reaction layers as irregular particles of the same glasses before flame-spraying. Microspheres based on the bioactive glass S53P4 were successfully produced through flame-spraying. Glass 13–93 microspheres were utilised as a reference composition with a known behaviour in flame spheroidisation. Bioactive glass microspheres (BGMs) enable a range of advantages compared to conventional irregular-shaped particles. The produced BGMs in size ranges of 45–90 and 90–125 µm were characterised by DTA, SEM/EDXA, FTIR, and XRD. Dynamic dissolution experiments were carried out using TRIS buffer and SBF (pH 7.4) for 72 h. The ion concentrations in the solutions were measured using ICP-OES. The in vitro bioactivity results indicated that the hydroxyapatite (HA) layer was thicker for the larger spheres after dissolution in SBF. According to the SEM-EDXA results, the S53P4 spheres showed a more rapid formation of the hydroxyapatite layer than the reference 13–93. The thermal and in vitro properties of the BGMs were similar to the particles of the parent glasses. The results suggest that microspheres based on S53P4 bioactive glass have an excellent potential for future clinical applications. [ABSTRACT FROM AUTHOR]

Purpose: Bioaccessibility is always a factor in human health risk assessment; the accurate determination of arsenic (As) dynamic dissolution in the gastric and small intestinal phases can provide a better understanding of its potential impact on human health. Materials and methods: Eighteen soil samples were collected from different sites in Hunan, China, and the factors controlling the bioaccessibility and dynamic dissolution of soil As were investigated. The bioaccessibility of soil As was determined by the physiologically based extraction test (PBET). Results and discussion: The results indicated that the bioaccessibility ranged from 6.9 to 59.5 % and 5.9 to 83.2 % in the gastric and small intestinal phases. Among all the soil properties, the concentrations of oxalate-extractable Fe, Mn, and total As were important for controlling bioaccessible As. In the gastric phase, the bioaccessible As concentrations increased rapidly in the first 20 min and kept steady state after 1 h. In the small intestinal phase, the bioaccessible As concentrations kept steady state rapidly after 2 h. Moreover, the more soluble fraction of As-bearing metal minerals had enhanced solubility in the gastric phase under acidic conditions, and most of the metal oxyhydroxides formed were usually unstable in the small intestinal phase under neutral conditions. By the interaction between kinetic laws and simple linear correlation, the dissolution rate of As for soils with lower pH was faster in the gastric phase; thus, the soil pH and dissolution of Fe, Mn, and Al minerals may be the main factors controlling the As dissolution rate. Conclusions: The As bioaccessibility in the small intestinal phase was higher, and the prescribed 4 h duration of the PBET method can meet As complete dissolution. The dynamic dissolution of As from soil in the gastric and small intestinal phases was strongly controlled by the concentrations of dissolved Fe, Mn, and Al. [ABSTRACT FROM AUTHOR]

Development of new pharmaceutical compounds and dosage forms often requires in vitro dissolution testing with the closest similarity to the human gastrointestinal (GI) tract. To create such conditions, one needs a suitable dissolution apparatus and the appropriate data on the human GI physiology. This review discusses technological approaches applicable in biorelevant dissolutions as well as the physiology of stomach and small intestine in both fasted and fed state, that is, volumes of contents, transit times for water/food and various solid oral dosage forms, pH, osmolality, surface tension, buffer capacity, and concentrations of bile salts, phospholipids, enzymes, and Ca2+ ions. The information is aimed to provide clear suggestions on how these conditions should be set in a dynamic biorelevant dissolution test. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 102:2995-3017, 2013 [ABSTRACT FROM AUTHOR]

Abstract: The purpose of this study was to predict the oral absorption of glyburide. Biorelevant dissolution methods, combined with permeability measurements and computational simulations, were used to predict the oral absorption of glyburide. The objective was to establish in vitro/in vivo correlations (IVIVCs) based on the biopharmaceutics drug classification system. The solubility of the glyburide powder was measured in different media. The dissolution behavior of two commercial tablet formulations was tested in different media. Two chemical grades of sodium taurocholate: low quality (LQ)=crude and high quality (HQ)=97% purity, and egg-lecithin: LQ=60% and HQ=99.1% purity were used to prepare fasted state small intestinal fluid (FaSSIF). Simulated intestinal fluid (SIF) and blank FaSSIF without lecithin and taurocholate (BL-FaSSIF) were used as controls. The dissolution tests were performed under constant pH and dynamic pH conditions. The dynamic pH range from 5.0 to 7.5 simulated the biological pH range of gastrointestinal (GI) tract in the fasted state. The drug permeability was studied using Caco-2 cell line. The predictions of the fraction dose absorbed were performed using GastroPlus™. The results of the simulations were compared with actual clinical data taken from a bioequivalence study. The solubility of glyburide was highest in LQ-FaSSIF. The two tablet formulations had significantly different dissolution behaviors in LQ-FaSSIF. The in vitro data was used as the input function into a simulation software. The dynamic LQ-FaSSIF dissolution data achieved the best prediction of the average AUC and C max of the clinically observed data. The present study shows that BCS based parameters combined with software simulations can be used to establish an IVIVC for glyburide. In vitro/in silico tools can potentially be used as surrogate for bioequivalence studies. [Copyright &y& Elsevier]

Objective: Studies have been performed using high- and low-copper amalgams to measure the amounts of mercury dissolution from dental amalgam in liquids such as artificial saliva; however, in most cases, mercury dissolution has been measured under static conditions and as such, may be self-limiting. This study measured the mercury release from low- and high-copper amalgams into flowing aqueous solutions to determine whether the total amounts of dissolution vary under these conditions when tested at neutral and acidic pH.Methods: High- and low-copper amalgam specimens were prepared and kept for 3 days. They were then longitudinally suspended in dissolution cells with an outlet at the bottom. Deionized water or acidic solution (pH1) was pumped through the cell. Test solutions were collected at several time periods up to 6 days or 1 month and then analyzed with a cold vapor atomic absorption spectrophotometer. After dissolution testing, the specimens were examined using SEM/XEDA for any selective degradation of the phases in the amalgam.Results: Except for the high-copper amalgam in the pH1 solution, the dissolution rates were found to decrease exponentially with time. The rate for the high-copper amalgam in pH1 solution slowly increased for 1 month. The total amounts (μg/cm2) of mercury released over 6 days or 1 month from both types of amalgam in deionized water were not significantly different (p≥0.05). The high-copper amalgam released significantly more mercury than the low-copper amalgam in the pH1 solution at both time periods. For both amalgams, the dissolution in pH1 was significantly higher than in deionized water.Significance: Mercury dissolution from amalgam under dynamic conditions is enhanced in an acidic media, and most prominently for a high-copper formulation. [Copyright &y& Elsevier]

The effect of carbonitrides on the growth of austenite grains in high-strength low-alloy (HSLA) steel was investigated through microstructure analysis and high-resolution dilatometry. The austenite grain growth at various temperatures was measured in situ using high temperature laser scanning confocal microscopy. Two kinds of precipitates with different morphologies containing large amounts of Ti and Nb were observed in the austenitized samples at different temperatures. The smaller Nb-rich spherical carbonitrides dissolved at the higher temperature, while the lager Ti-rich rectangular carbonitrides have a higher thermal stability and can pin at the austenite grain boundary. This study reveals that the dissolution of Nb in austenite causes the rapid growth of austenite grains and slows down the ferrite phase transition, which is beneficial to the formation of bainite. A kinetic model of austenite growth considering the dynamic dissolution of different types of carbonitrides is proposed. The results of the model show the same overall trend as the experimental results, and the individual differences can be explained. The proposed model can be used to predict the austenite grain size during the austenitizing process of HSLA steel and can reflect the austenite grain change throughout the process more continuously. • Two carbonitrides with different thermal stability at the high temperature were found. • The dissolution of Nb element affect the austenite grain size and also affect the phase transition in the cooling process. • Providing a new method to predict the pinning pressure and the austenite grain size with increasing time from dynamics. [ABSTRACT FROM AUTHOR]

The microstructure and texture evolution of the Al–Cu–Mg–Ag alloy were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). Results shown that the dynamic dissolution of the second phase particles occurs preferentially in the grain boundaries of the small DRX grains during hot rolling. The dynamic dissolution can be accelerated by the dislocation diffusion and the diffusion of DRX grain boundaries. The textures of α -fibre (<011>//ND) and θ -fibre (<001>//ND) are formed in the outer layer of the Al alloy whereas the textures of α -fibre and β -fibre are formed in the center layer of the Al alloy. With increasing rolling reduction, the textures at α -fibre are almost vanishing, only the θ -fibre H texture can be steadily formed in the outer layer. For the center layer, the Brass texture can be steadily formed. The evolution of texture in outer and center layers is related to the dynamic recovery and the dynamic recrystallization, respectively. • The dynamic dissolution of second phases during hot rolling was investigated. • The nucleation mechanism based on the dislocation walls was proposed. • The evolution of microstructure and texture was investigated. [ABSTRACT FROM AUTHOR]

Tissue plasminogen activator (tPA) is the sole approved therapeutic molecule for the treatment of acute ischemic stroke. Yet, only a small percentage of patients could benefit from this life-saving treatment because of medical contraindications and severe side effects, including brain hemorrhage, associated with delayed administration. Here, a nano therapeutic agent is realized by directly associating the clinical formulation of tPA to the porous structure of soft discoidal polymeric nanoconstructs (tPA-DPNs). The porous matrix of DPNs protects tPA from rapid degradation, allowing tPA-DPNs to preserve over 70% of the tPA original activity after 3 h of exposure to serum proteins. Under dynamic conditions, tPA-DPNs dissolve clots more efficiently than free tPA, as demonstrated in a microfluidic chip where clots are formed mimicking in vivo conditions. At 60 min post-treatment initiation, the clot area reduces by half (57 ± 8%) with tPA-DPNs, whereas a similar result (56 ± 21%) is obtained only after 90 min for free tPA. In murine mesentery venules, the intravenous administration of 2.5 mg/kg of tPA-DPNs resolves almost 90% of the blood clots, whereas a similar dose of free tPA successfully recanalizes only about 40% of the treated vessels. At about 1/10 of the clinical dose (1.0 mg/kg), tPA-DPNs still effectively dissolve 70% of the clots, whereas free tPA works efficiently only on 16% of the vessels. In vivo, discoidal tPA-DPNs outperform the lytic activity of 200 nm spherical tPA-coated nanoconstructs in terms of both percentage of successful recanalization events and clot area reduction. The conjugation of tPA with preserved lytic activity, the deformability and blood circulating time of DPNs together with the faster blood clot dissolution would make tPA-DPNs a promising nanotool for enhancing both potency and safety of thrombolytic therapies.